Full-scale performance evaluation of mobile roof supports.
Barczak TM; Gearhart DF
Proceedings: New Technology for Ground Control in Retreat Mining, Pittsburgh, PA: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 97-133, IC 9446, 1997 Mar; :99-126
Two mobile roof supports (MRS's), one manufactured by J. H. Fletcher and Company and one manufactured by Voest-Alpine Mining and Tunneling, were evaluated under controlled load conditions in the Strategic Structures Testing Laboratory at the Pittsburgh Research Center. A unique load frame, called the mine roof simulator, provided a realistic simulation of mining conditions by inducing vertical, horizontal, and lateral loading on the support. The purpose of these tests was to determine the performance capabilities and limitations of the supports and to investigate factors that influence the measurement of loading and loading rate. An evaluation of the support design and load conditions that can cause support failure or loss of support capacity is presented relative to the laboratory tests. In general, lateral loading perpendicular to the longitudinal axis of the canopy is most severe, although horizontal loading in the direction of the longitudinal axis of the canopy can also produce critical loading is some cases. The tests indicate that both setting force and leg pressure measurement are influenced by the staging of the leg cylinders. The implications of these factors on load rate measurement are evaluated. Differences in design philosophy between the two supports are identified and related to support performance. The difference in leg design, two- versus three-stage, had the most impact on support performance. Safety issues pertaining to support operation and maintenance are also discussed. Lastly, MRS capacity and stiffness characteristics are compared with those of conventional timber supports.
Mining-industry; Underground-mining; Accident-prevention; Coal-mining; Mining-equipment; Injury-prevention
Proceedings: New Technology for Ground Control in Retreat Mining